Prevalence and Correlates of Adynamic Bone Disease in Patients with Kidney Failure in Singapore

Background/Objectives: The spectrum of chronic kidney disease-mineral and bone disorder (CKD-MBD) is changing and adynamic bone disease (ABD) is now believed to constitute the majority of CKD-MBD in the developed world. However, its prevalence and risk factors are poorly described in literature. Its diagnosis requires bone biopsy but biochemical criteria including parathyroid hormone (PTH) levels show good correlation. The aim of this study is to understand the prevalence of ABD in our patients with kidney failure (KF) on hemodialysis (HD), identify the risk factors for its development, and in doing so enable early intervention to modify the risk factors specific to our population. Methods: This is a retrospective cross-sectional study. 201 prevalent adult patients on maintenance HD for at least 3 months were recruited. Patients with previous parathyroidectomy were excluded. Relevant data including clinical and biochemical parameters, prescribed dialysate and medications, and clinical outcomes were collected. ABD was diagnosed if any intact PTH (iPTH) level during the study period was <15pmol/L. Results: Of the 201 patients in the study (median age 64.5 years), 35 (17.4%) patients had ABD. In the multivariable logistic regression model, the adjusted odds ratio (OR) of ABD was higher with higher mean adjusted serum calcium level while concurrent use of non-calcium-based binders was associated with lower odds of ABD. Activated vitamin D use was also associated with lower odds of ABD likely reflecting past occurrence of ABD prompting a pre-emptive discontinuation of activated vitamin D. 17% of patients had had fractures without significant association with ABD. The mean PTH level was in the target range (15-60pmol/L) in 41% of the cohort. Cardiovascular complications were not significantly associated with ABD. Conclusions: Approximately one in every six HD patients in our care have ABD as diagnosed by the iPTH level. Targeting a lower serum calcium level and using non-calcium-based binders may reduce the occurrence of ABD and will need to be tested in prospective studies.